Synthesis of 1,2,3-triazole-substituted coumarins and also 1,2,3-triazolyl or 1,2,3-triazolylalk-1-inyl-linked coumarin-2,3-furocoumarin hybrids was performed by employing the cross-coupling and copper catalyzed azide-alkyne cycloaddition reaction approaches. The synthesized compounds were evaluated for their in vitro antibacterial activity against Staphylococcus aureus, Bacillius subtilis, Actinomyces viscosus and Escherichia coli bacterial strains. Coumarin-benzoic acid hybrids 4с, 42с and 3-((4-acetylamino-3-(methoxycarbonyl)phenyl)ethynyl)coumarin (29) showed promising activity against S. aureus strains, and the 1,2,3-triazolyloct-1-inyl linked coumarin-2,3-furocoumarin hybrid 37c was endowed with high selectivity against B. subtilis and E. coli species. The in vitro antibacterial activity of 4с, 29, 37c and 42с can potentially be compared with that of a number of modern antibiotic drugs used in the clinic, suggesting promising prospects for further research. A detailed study of the molecular interactions with the targeted protein MurB was performed using docking simulations and the obtained results are quite promising.

A convenient protocol for the rapid and efficient synthesis of 3bromopeuruthenicin 2 from plant coumarin peuruthenicin 1 is described. Coumarin 2 have been successfully reacted with Nmethylpiperazine, or 5-aminoisoquinoline under reflux in chloroform with the formation of 3-(N-substituted)aminoumbelliferons. The easiness of formation of the mentioned compounds can be explained by occurring of the tautomerization processes in 3-bromo-7-hydroxycoumarin 2 in the reaction conditions. For obtaining high yields of 3-(arylamino)coumarins in the reaction of 3-bromocoumarin 2 with substituted anilines the palladium-catalyzed C-N coupling reaction was studied. The reaction proceeded cleanly in the presence of the Pd (OAc) 2 -Xantphos catalytic system with the formation of the corresponding coupling products. The Suzuki cross-coupling reaction of 3-(3-bromophenylamino)coumarin 8 f with aryl-and (hetaryl)boronic acids 11,13 and 14 using PdCl 2 (dppf) as the catalyst provided the formation of 3-(N-(aryl-hetaryl))aminocoumarins 12, 15 and 16 in good yields. The cytotoxicity of new umbelliferone derivatives was evaluated against human cancer cells using the conventional MTT assays. The data revealed that compounds 12, 15 and 16 possessed most promising cytotoxic potential; aminocoumarins 12 and 16 shown selectivity toward the breast cancer cells MCF-7. The cytotoxicity of 3-(N-substituted)aminocoumarins 12 and 16 on this cell lines was comparable to those of standard drug Doxorubicin.[a] Dr.

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